1. Field
The present disclosure relates to methods and apparatuses for a piezoelectric energy harvester, and more particularly, to a piezoelectric energy harvester for generating electric energy by using a mass, and a mobile device having the piezoelectric energy harvester.
2. Description of the Related Art
Piezoelectric energy harvesting technology is eco-friendly energy technology that converts mechanical energy, such as vibrations, shocks, sound, etc., which are generated everywhere, into electrical energy by using a piezoelectric material, and the converted electrical energy is stored. A typical piezoelectric energy harvester may be a cantilever type piezoelectric energy harvester, in which a piezoelectric device is deformed as an elastic member vibrates and thus electrical energy is generated. In the cantilever type piezoelectric energy harvester, a resonance mode or a mass may be used to obtain a high power. In addition to the above, there have been many other researches about piezoelectric energy harvesters that may harvest a large amount of electrical energy from a relatively small amount of mechanical energy. On the other hand, since the piezoelectric energy harvester may not be used as a power source when external mechanical energy is not continuously received, a storage device such as a battery or capacitor to store converted electrical energy, is needed.